High speed visible-light communication using organic light-emitting diodes based on fluorescent and phosphorescent emitters (dataset)

Visible light communications (VLCs) using organic light-emitting diodes (OLEDs) are a promising technology because of unique features of OLEDs such as arbitrary sizes and shapes, and providing a glare-free illumination. However, the reported best data transmission rate of OLEDs in VLC, so far, are quite low (~50 Mbps), even in unpractical short data link (12.5 cm). To enhance the data rate, high signal-to-noise-ratio and high modulation bandwidth is required. Here, we report a systematic investigation of OLEDs, in particular, the influence of light emitting materials and device size. Because both points are related on both signal-to-noise-ratio and the bandwidth, and they have fundamental trade-off in data rate, the understanding of the influence on the data rate will be basics to improve furthermore the date rate. However, in the early stage of development of OLEDs for VLCs, their influence were not investigated. Through the investigation, we found that a conventional fluorescent emitter, 2,5,8,11-tetra-tert-butylperylene, with the smallest device area of 1.2 × 10-3 cm2 are important to achieve higher data transmission rate. That means that the enhancement of data rate by increasing the bandwidth is much effective than the enhancement of the data rate by increasing radiance. Through these investigation, we achieved a record data transmission rate of 663 Mbps with an implementation of orthogonal frequency-division multiplexing, which is the 13 fold improvement of the data rate from the best data rate reported so far even in more practical 2 m data link.基于有机发光二极管（OLED）的可见光通信（VLC）凭借OLED独特的性能优势（如可定制任意尺寸与形状、实现无眩光照明），是一项极具应用前景的技术。然而，截至目前，即便在极短的非实用化通信链路（12.5 cm）中，已报道的OLED可见光通信最高数据传输速率仍仅约50 Mbps，处于较低水平。为提升数据传输速率，需同时具备高信噪比与高调制带宽。本研究针对OLED开展系统性研究，重点探究发光材料与器件尺寸对通信性能的影响。由于这两类因素同时关联信噪比与调制带宽，且二者在数据传输速率上存在本质的权衡关系，因此厘清其对数据速率的影响机制，将为进一步提升数据传输速率奠定基础。然而在OLED可见光通信技术发展初期，这两类因素的影响尚未得到系统研究。本研究发现，采用常规荧光发射材料2,5,8,11-四叔丁基苝（2,5,8,11-tetra-tert-butylperylene）且器件面积最小为1.2×10^-3 cm²的OLED体系，可实现更高的数据传输速率。这表明通过提升调制带宽来优化数据传输速率的效果，远优于通过提升辐射亮度实现的速率提升。通过本次研究，我们结合正交频分复用（orthogonal frequency-division multiplexing, OFDM）技术，实现了663 Mbps的创纪录数据传输速率；即便在更具实用价值的2 m通信链路中，该速率也较此前已报道的最高水平提升了13倍。